 /*******************************************************************************
  * Copyright (c) 2005 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.internal.actions;

 import org.eclipse.jface.action.Action;
 import org.eclipse.swt.custom.BusyIndicator;
 import org.eclipse.ui.IWorkbenchPreferenceConstants;
 import org.eclipse.ui.IWorkbenchWindow;
 import org.eclipse.ui.PlatformUI;
 import org.eclipse.ui.actions.ActionFactory.IWorkbenchAction;
 import org.eclipse.ui.internal.IWorkbenchHelpContextIds;
 import org.eclipse.ui.internal.WorkbenchMessages;
 import org.eclipse.ui.internal.util.PrefUtil;

 /**
  * Action to open the dynamic help.
  *
  * @since 3.1
  */
 public class DynamicHelpAction extends Action implements IWorkbenchAction {
     /**
      * The workbench window; or <code>null</code> if this action has been
      * <code>dispose</code>d.
      */
     private IWorkbenchWindow workbenchWindow;

     /**
      * Zero-arg constructor to allow cheat sheets to reuse this action.
      */
     public DynamicHelpAction() {
         this(PlatformUI.getWorkbench().getActiveWorkbenchWindow());
     }

     /**
      * Constructor for use by ActionFactory.
      *
      * @param window
      * the window
      */
     public DynamicHelpAction(IWorkbenchWindow window) {
         if (window == null) {
             throw new IllegalArgumentException ();
         }
         this.workbenchWindow = window;
         setActionDefinitionId("org.eclipse.ui.help.dynamicHelp"); //$NON-NLS-1$

         // support for allowing a product to override the text for the action
 String overrideText = PrefUtil.getAPIPreferenceStore().getString(
                 IWorkbenchPreferenceConstants.DYNAMIC_HELP_ACTION_TEXT);
         if ("".equals(overrideText)) { //$NON-NLS-1$
 setText(appendAccelerator(WorkbenchMessages.DynamicHelpAction_text));
             setToolTipText(WorkbenchMessages.DynamicHelpAction_toolTip);
         } else {
             setText(appendAccelerator(overrideText));
             setToolTipText(Action.removeMnemonics(overrideText));
         }
         window.getWorkbench().getHelpSystem().setHelp(this,
                 IWorkbenchHelpContextIds.DYNAMIC_HELP_ACTION);
     }

     private String appendAccelerator(String text) {
         // We know that on Windows context help key is F1
 // and cannot be changed by the user.
 //
 // Commented out due to the problem described in
 // Bugzilla bug #95057

         //if (Platform.getWS().equals(Platform.WS_WIN32))
 // return text + "\t" + KeyStroke.getInstance(SWT.F1).format(); //$NON-NLS-1$
 return text;
     }

     /*
      * (non-Javadoc) Method declared on IAction.
      */
     public void run() {
         if (workbenchWindow == null) {
             // action has been disposed
 return;
         }
         // This may take a while, so use the busy indicator
 BusyIndicator.showWhile(null, new Runnable () {
             public void run() {
                 workbenchWindow.getWorkbench().getHelpSystem()
                         .displayDynamicHelp();
             }
         });
     }

     /*
      * (non-Javadoc) Method declared on ActionFactory.IWorkbenchAction.
      */
     public void dispose() {
         workbenchWindow = null;
     }

 }

